Crank Brothers Multi-17 Tool
The Crank Brothers Mini Multi 17 tool has everything you need. It'll fit in your pocket or any seat bag for easy access when you need it.
Has to be my favorite multi tool on the market. Really can do about any trail repair or adjustment needed with this. The chain tool isnt perfect and I find it maxing out sometimes before the pin is pushed far enough out, but i would rather that than accidentally completely releasing the pin. Spoke wrenches can scratch up your rim due to how wide the square piece they are in, but those are both more home repairs than trail.